bsnes/higan/fc/apu/pulse.cpp

34 lines
679 B
C++

auto APU::Pulse::clockLength() -> void {
if(envelope.loopMode == 0) {
if(lengthCounter) lengthCounter--;
}
}
auto APU::Pulse::clock() -> uint8 {
if(!sweep.checkPeriod()) return 0;
if(lengthCounter == 0) return 0;
static const uint dutyTable[] = {1, 2, 4, 6};
uint8 result = (dutyCounter < dutyTable[duty]) ? envelope.volume() : 0;
if(sweep.pulsePeriod < 0x008) result = 0;
if(--periodCounter == 0) {
periodCounter = (sweep.pulsePeriod + 1) * 2;
dutyCounter++;
}
return result;
}
auto APU::Pulse::power() -> void {
envelope.power();
sweep.power();
lengthCounter = 0;
duty = 0;
dutyCounter = 0;
period = 0;
periodCounter = 1;
}